Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Nomeie o número total de oponentes no local para Oklahoma.
 ###Tabelas: CREATE TABLE racing_vehicles (racing_vehicles_id AUTO_INCREMENT PRIMARY KEY, Model VARCHAR, Year VARCHAR, Type VARCHAR, Engine VARCHAR, Displacement cc VARCHAR) CREATE TABLE collaboration_singles (collaboration_singles_id AUTO_INCREMENT PRIMARY KEY, Year INT, U.S. Hot 100 VARCHAR, U.S. R&B VARCHAR, U.S. Rap VARCHAR, Album VARCHAR) CREATE TABLE democrats (democrats_id AUTO_INCREMENT PRIMARY KEY, Candidate VARCHAR, Total Receipts INT, Loans Received INT, Receipts w/o Loans INT, Money Spent INT, Cash On Hand INT, Total Debt VARCHAR, Cash on Hand Minus Debt INT) CREATE TABLE pga_tour_professional_career_summary (pga_tour_professional_career_summary_id AUTO_INCREMENT PRIMARY KEY, Year INT, Starts INT, Cuts made VARCHAR, Wins (Majors) VARCHAR, 2nd INT, 3rd INT, Top 10 INT, Top 25 INT, Earnings ($) INT, Money list rank INT, Adjusted scoring average (rank) VARCHAR) CREATE TABLE record_vs._big_12_opponents (record_vs._big_12_opponents_id AUTO_INCREMENT PRIMARY KEY, Missouri vs. VARCHAR, Overall Record VARCHAR, at Columbia VARCHAR, at Opponents Venue VARCHAR, at Neutral Site VARCHAR, Last 5 Meetings VARCHAR, Last 10 Meetings VARCHAR, Current Streak VARCHAR, During Time in Big 12 VARCHAR)  
SELECT COUNT at Opponents Venue FROM record_vs._big_12_opponents WHERE Missouri vs. = Oklahoma